We now have the knowledge and clues to formulate a picture of how our solar system formed. Any theory of the formation of the solar system must address and explain the following phenomena:

1. The orbits of the planets and most of the planetary satellites all lie in roughly the same plane -- the plane of the ecliptic.
   
   
2. Nearly all the planets and satellites orbit and rotate in the prograde direction -- counterclockwise as viewed from the north.
   
   
3. Most planets and satellites have axis tilts less than 30 degrees.
   
   
4. Most planets and satellites have nearly circular orbits.
   
   
5. The terrestrial planets are made of rock; the outer planets are made primarily of gas, and their satellites get icier and icier the further out you go.
   
   
6. The outer planets are large (except Pluto) but have low densities; the inner planets are small, but have high densities.
   
   
7. The Jovian planets have large satellite systems and rings.
   
   
8. The Jovian planets rotate more rapidly than the terrestrial planets.
   
   
9. The Sun has a slow rotation period -- 25 days.

Any would-be theory of the origin of the solar system must explain all the above phenomena. Oddities like Uranus, Venus, Pluto, Phoebe, etc. need not be addressed... at least not right away.

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